The present invention relates to a continuous cycle absorption refrigerating unit, intended in particular for refrigerators in vehicles, whose solution contains a corrosion inhibitor. In view of the various possible types of operation of absorption refrigerator units (electric heating or heating by combustion of gaseous or liquid fuels) this type of refrigerator finds extensive use in land and water vehicles.
In the case of the use of absorption refrigerating units which are installed permanently in vehicles, the unit may tilt with respect to the vertical by an amount which exceeds the inclination of the liquid-conducting tubes with respect to the horizontal. This results in a substantial accumulation of liquid in the liquid circuit outside an reservoir or absorber vessel 11 (see FIG. 1). As a result of this accumulation, the level 12 of the liquid in reservoir 11 drops. Furthermore, the height of the lower end of the thermosiphon pump 16 can change with respect to the original liquid level 12. Under such conditions, the inclination of the refrigerator has the effect of changing the depth of immersion of the pump 16. The maximum angle of inclination at which the thermosiphon pump 16 is still just able to pump liquid will be referred to hereinbelow as the "permissible angle of inclination". If the permissible angle of inclination of the refrigerator is exceeded, then the pump is no longer minimally immersed and only a vapor mixture of coolant and solvent is expelled from the pump. As a result, there is a considerable enrichment of the corrosion inhibitor in the remaining solution which leads to a substantial increase in the density of the solution. The high density solution drops to the lowest point in the forward path 13 and is replaced by solution rich in coolant. This solution, in turn, is subjected to the same evaporation process. If the unit is operated for a long time with an impermissible inclination, a solution of relatively low coolant content and extremely high inhibitor content will be located in the entire forward path 13. This solution has a higher boiling point and specific gravity than the solution which fills the path 13 during normal conditions. If these variables assume sufficiently high values, the pumping action of the pump is lost even after the unit is returned to a normal operating position. The main reasons for this are:
(a) The difference in the boiling points between the lean solution in the generator 1 and the solution contained in the vapor-producing end of the liquid heat exchanger 15 becomes so small that the heat transfer does not produce sufficient vapor to operate the thermosiphon pump.
(b) Due to the high density of the solution in the forward path 13, the communicating liquid level 21 in the vapor-forming end of the liquid heat exchanger 15 is lower than the liquid level 12 in the reservoir 11, which can also limit or prevent the pumping action of the pump.
The primary object of the present invention is to create a refrigerating unit which, even after it has been inclined for hours with an inclination greater than the permissible angle of inclination, can resume normal operation immediately after the unit is placed at an inclination which is less than the permissible value.